In this article we will consider the VAZ-2107 car (injector). Carburetor models are simply bypassed, as they have long been outdated morally. As for injection (with forced injection of the fuel mixture), they are by far the most common. The modern automotive industry has completely abandoned carburetor systems. What elements are in the injection system and absent in the carburetor? In this article we will try to find out.
How does the injection system work?
The essence of the whole process is that gasoline is supplied under pressure to the fuel rail, in which it is mixed with purified air in a ratio of 14 to 1. The mixture is always under pressure, so when it opens the valve, it enters the combustion chamber unhindered. Ignition occurs here and the piston makes a stroke. In this case, the crankshaft rotates, and the car is set in motion.
A lot of sensors are responsible for the normal operation of all nodes, which measure the temperature, pressure, amount of air and gasoline, etc. All signals are sent to the microcontroller control unit. It contains a special algorithm that regulates the operation of all the main components and mechanisms. Here we will talk about the VAZ-2107 engine (injector) in our article. And more precisely - about its components.
Crankshaft sensor
This is one of the important readers, available on any injection motor, including the "sevens". With its help, the speed of the crankshaft is read. If you look closely at the design of the entire assembly, you can see that the sensor is installed opposite the teeth of the crankshaft pulley. And it is clear that the distance between the teeth is the same, but not everywhere. There is a gap in which two teeth are missing - it is this stretch that is the "master." The sensor picks it up and starts to count a new pulley revolution.
Using this device, the number of revolutions is recorded. Based on the data received from the sensor, the electronic control unit decides to increase or decrease the amount of air or gasoline in the mixture. But this is not all; other devices also affect the work, which we will talk about later.
Air flow sensor
This is a device that allows you to record the amount of air that enters the fuel rail. The design is based on a platinum thread, which in some cases becomes dirty. To extend the life of this device, it is necessary to change the air filter in a timely manner. If the degree of contamination is small, it is allowed to clean the thread with a means for washing the injectors.
The essence of the work is that the thread warms up to a certain temperature. When air passes through the tube, the thread cools by several degrees. The logic installed in the control unit calculates the amount of air that enters the ramp. This is the easiest way to calculate the air entering the ramp to form a mixture.
Speed sensor
Using this device, the vehicle’s speed is measured. Data is supplied not only to the electronic control unit, but also to the speedometer to inform the driver about the current speed. The device is placed directly on top of the gearbox.
Camshaft sensor
It is installed, as the name implies, on the camshaft. This is one of the devices with which it turns out to set the correct ignition. There is no distributor on the VAZ-2107 (injector), a spark is generated using logic elements based on data received from readers.
Ignition system
On carburetor engines there were mechanical type ignition distributors (both non-contact and contact). But they all have one big drawback - friction to a greater or lesser extent is still present, so the reliability of the whole mechanism is low.
As for injection engines, then they read all the parameters using sensors. The signals are fed to the electronic control unit, then processed. Logic allows you to adjust the ignition timing and the moment of fuel injection into the combustion chamber. Candles and armored wires are used exactly the same as on carbureted engines.
It is worth noting that modern cars are equipped with an ignition system, in which a separate coil is installed on each candle, a low-voltage wire is connected to it. In such a simple way, the presence of high voltage under the hood was avoided.
Flap position sensor
A throttle is a unit that allows you to change the amount of air supplied to the fuel rail. In fact, when you press the accelerator pedal, you increase the amount of air, not gasoline. Already on the basis of how much oxygen entered the ramp, an increase or decrease in the volume of gasoline will occur. In total, there are two types of sensor designs:
- Resistive.
- Non-contact.
The first ones are similar in principle to volume controls in household appliances. They have one big drawback - there are rubbing surfaces, so often the device fails. Generation is present, usually at the very beginning of the track. If the position sensor breaks down, a frequent idle change on the VAZ-2107 will be observed (the injector cannot understand what position the pedal is in, since the resistance of the sensor is unstable).
The proximity sensor is deprived of such drawbacks (it works by the encoder principle). But the cost is much higher, so ordinary drivers rarely install them on their cars.
Fuel injectors
These are one of the main components, their cleaning and replacement with a VAZ-2107 (injector) should be done in a timely manner. The nozzle resource is also affected by filters. In fact, nozzles are solenoid valves that stand in the way of the movement of the fuel mixture. The electronic control unit gives a command to open and close them, focusing on the readings of the sensors.
To protect the electrical circuits, fuses are installed in the mounting block. On the VAZ-2107 (injector), all components are protected, and the nozzles must be turned on by means of an electromagnetic relay, since they have a large consumption current.
Fuel pressure sensor
This device is necessary so that high pressure does not form in the fuel rail. A pump located in the tank pumps gasoline through the pipelines into the fuel rail to a certain pressure. It should be enough for the mixture to be injected into the combustion chamber. The sensor is mounted directly on the ramp, and when the maximum permissible pressure value is exceeded, excess is released through the non-return valve into the line connected to the tank. The principle of operation is approximately the same as that of the expansion tank cap in the cooling system.
The Lambda probe
This is a sensor that allows you to estimate the oxygen content in the exhaust gases. It should be noted that you cannot directly measure, so you have to install a sensitive element inside the exhaust pipe and outside. And to improve sensitivity, it is necessary to warm up the device to 600 degrees.
Using this sensor, the ignition timing is set and the quality of the fuel mixture is regulated. The presence of the device is due to the introduction of toxicity standards.
How does the fuel injection system work?
And now let's talk about how the fuel injection system works. So, from the very beginning:
- You turn the ignition key, power is supplied to the electronic control unit, all sensors and actuators.
- After the start of crankshaft rotation, the VAZ-2107 generator (injector) starts working as a starter.
- All sensors record a change in the parameters that they measure.
- The electronic control unit adjusts the quality of the mixture and adjusts the ignition timing.
- The mixture under pressure is fed into the combustion chambers through open nozzles, the ignition process and the working cycle begin.
That's all - the engine started, all its components are working. When you press the accelerator pedal, you increase the amount of air, therefore, gasoline. The crankshaft speed will also increase.